cosmid stability

Brad Nicholson brad at
Tue Jul 18 19:34:23 EST 1995

In article <wjia.1156500368A at>, wjia at (William 
Jia) wrote:

> We are trying to use cosmid to accomodate a large fraction of viral DNA 
 >found it is very unstable. I would appreciate if anybody can tell me any
 >other system beside cosmid that can accomodate a large DNA fragment but 

Hello William,
Have you considered using a low copy number cosmid?  There is an Amp-R 
cosmid that is about 3-4 copies/cell.  It can help stabilize problem DNA's,
although it doesn't work on everything (My first thesis project.).  

Alternatively you can try using the same systems with different strains, 
recA, (run of the mill) recBJ,sbcC (Stratagene, SURE).

Although I have never used it, phage P1 is supposed to be stable and it 
takes whopping big hunks, 80 - 100 Kb I believe. (Du Pont, Sternberg. 
(1990). Proc. Natl. Acad. Sci. USA. 87, 103-107.

Good Luck, 
Brad Nicholson              |"If it worked the first time, it wouldn't be 
Department of Pathology     |	research."...Brad Nicholson
University of Utah          |	Live from behind the Zion Curtian.
Salt Lake City, UT 84132    | 
brad at    |
or: (801)-581-4365          | My opinions are solely my own.

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